The series features countless creatures with cute exteriors and deeply disturbing backstories. On its surface, the Pokémon franchise is about joyous exploration and competition with semi-sentient animal-esque creatures with supernatural powers.
However, the reality is that the Pokémon universe is absolutely terrifying when examined at a closer level. Not only is it a world where animal fighting is the pre-eminent sport, but it's also a land where children are encouraged to go on cross-country trips by themselves while putting themselves in constant danger.
In addition to the big logical holes in how Pokémon society works, many Pokémon have frankly horrifying backstories. Not only do some Pokémon delight in torturing and feasting on lesser Pokémon species for sport, but others also have supposed origins pulled straight out of ghost stories that would keep you up at night.
And while some Ghost-type or Dark-type Pokémon are expected to have horrifying backstories, many cute Pokémon also have some very dark stories tied to them. The Ground/Ghost-type Sandygast appears to be a humble sandcastle with a small sand trowel sticking out of its head.
However, this unassuming Pokémon actually possesses victims to help it grow. According to s Pokédex entry, " As for Sandygast's origins, the Pokémon is actually an accumulation of the «grudges of the dead» that has possessed a child's sandcastle.